Starting next Tuesday, your morning coffee to go will come with a full disclosure of its caloric content.

Starbucks has announced that it will include calorie counts for each beverage on the menu boards at all of its more than 11,000 locations in the U.S., as well as tags for pastries in the bakery cases.

In a news release about the new feature, Mary Wagner, the senior vice president of global research and development at Starbucks, said: “Menu labeling is yet another step to extend our commitment to wellness, ensuring our customers and partners (employees) have the information they need to make informed decisions and understand all the ways that they can customize their Starbucks beverages to be within their desired calorie range.”

The company already offers nutrition information on its products online and through printed brochures. It started offering sugar-free syrup in its drinks in 1997 and stopped using high-fructose corn syrup in its baked goods in 2009.

Nutrition experts argue that such transparency about the nutritional and caloric content of foods that people consume on the go and in restaurants could help to curb overeating and lower obesity rates. But the data supporting this idea are conflicting. Studies do show that people tend to underestimate the amount of calories they consume, especially while eating out. Last month, researchers reported in BMJ that diners who frequented fast-food chains like McDonald’s, Burger King, Wendy’s, KFC, Subway and Dunkin’ Donuts, thought they consumed far fewer calories than they actually did; adults and kids underestimated the caloric content of their meals by 175 calories, while adolescents were off by 259 calories.

But whether having caloric information on menus actually changes people’s eating habits isn’t as clear. In New York City, where larger fast-food chains and outlets like Starbucks have been required to post calorie information since 2008, some studies showed no change in how much people ate, while others showed that only one-sixth of consumers were motivated by the information to order lower-calorie options.

Why? Some public-health experts argue that without putting the calories into some kind of context, simply attaching these tallies to menus won’t be effective. In a recent editorial for theNew England Journal of Medicine, two Johns Hopkins obesity experts wrote, “If customers don’t understand what 250 calories means or how those calories fit into their overall daily dietary requirements, posting that information on a menu may not be very useful. That difficulty may apply particularly to minority populations and those with low socioeconomic status, who are at highest risk for obesity and tend to have lower-than-average levels of nutritional literacy and numeracy, which may make it difficult for them to translate the information into interpretable equivalents.”

In fact, Dr. Dariush Mozaffarian, an associate professor of medicine and epidemiology at Harvard Medical School and Brigham and Women’s Hospital, finds that there is little scientific evidence confirming the effectiveness of adding calorie counts to menus in order to improve health. He says people may end up substituting unhealthy, albeit lower-calorie options, in at attempt to lower their caloric intake. Mozaffarian and his colleagues published their findings as a formal scientific statement from the American Heart Association. He told TIME in May:

If [the food industry] responds to that by decreasing portion sizes, that would be great, but if they respond by taking out healthy fats, which is one of the easiest ways to reduce calories, that’s not. For consumers, if you made a choice solely based on menu-calorie labels, you may choose soda over nuts calorie-wise, which is a terrible decision.

To address some of these problems, other nutrition experts are hoping to see different information on menu boards, like how much physical activity it might take to work off that frappuccino, so consumers can really understand how much they’re eating. A small study testing this idea showed that it could work; those who used menus with physical activity information ordered fewer calories than those who only had caloric content tallies.

All of this data will soon become critical as the U.S Patient Protection and Affordable Care Act requires that any restaurant chain with over 20 locations in the U.S. must post calorie counts on their menus by 2014. Starbucks and other food retailers such as McDonald’s, Au Bon Pain and Panera Bread are hoping to get ahead of the mandate by adding calorie counts now, but whether the move will help their customers eat less is a question that neither they — nor the experts — can answer yet.

I think anything that helps people make better choices is a win/ win, but the food industry does a good job of addicting people to their products so that they have customers for life. Now, I grow most of my food, but, I do love me the occasional KFC dinner or just something tasty even though I know its loaded with calories. But I workout every day, I know what it's like to be 390 lbs at 5'7" ya know, being able to count calories helped me workout and diet and be the 165 lb lean muscle guy I am today. So, if anything helps anyone that whats to help them self, it can't hurt.

It won't affect much. If you're calorie conscious, you would know that Starbucks has carried a take-away pamphlet with calorie counts, as well as a customized calorie section for their drinks and food items.. complete with modifications most people make when ordering. I believe posting this will only numb people's attention toward calories and food... we have GOT to stop playing this calorie game like it's nothing to worry about.. seeing that a tiny loaf cake at Starbucks packs almost 400 calories, whereas you can enjoy a meal of whole foods for the same amount, is horrifying. Did you know a certain pastry item at Starbucks that's the size of a ping pong ball has 310 calories in it? SMH

Don't care about carb. If you are fat, don't drink it or drink a small cup just for the taste. No one ask you to get a jumbo size coffee. When startbuck start using soya inside some of the product like the strawberry smoothie, I stop drinking it because the new product taste like crap and texture is not right. Eat the real thing and eat less and exercise. You sit all day you are going to get fat anyway even if you just eat apple since you intake food and no burn any away.